Armature/Bone Heat Failed
I would reccommend a few things:


Start with the bird in an easy rest position:
Right now you have it set so that the wings are in an up position. This can complicate rigging and could result in artifacts when the wings are in the down position.
If automatic weights do not work, you may need to weight paint manually: Automatic weights are designed to be a time saver, but may not work in all instances. It may become necessary for you to paint the weights manually


You may want to watch a few rigging tutorials and try to apply those concepts to this project, as I think there is no one right answer, but rather a set of toolsets that can be applied to each situation depending on the conditions.